1. Technical Field
A substitute for a mechanical valve with moving parts for fluid dispensing instruments such as writing instruments and painting instruments is disclosed. More specifically, instead of a mechanical valve such as a ball valve, needle valve, or duck bill valve, a combination of filters is substituted for a mechanical valve. Still more specifically, a combination of hydrophobic and hydrophilic filters are used to control the flow of ink, paint correction fluid or any other water based fluids from a flexible barrel reservoir to the tip, brush or applicator of the instrument. Still more specifically, a hydrophobic filter media is disposed between the fluid supply and a hydrophilic filter media. The hydrophilic filter media is disposed between the brush tuft, pen tip or applicator tip and the hydrophobic filter media. Manual pressure applied to the flexible barrel holding the fluid will force the fluid through the hydrophobic filter media and to the hydrophilic filter media. The hydrophilic filter media will deliver a controlled flow of fluid to the applicator tip.
2. Background of the Related Art
In fluid dispensing instruments such as ink pens, gravitational and capillary forces are the two principal means for migrating ink from the reservoir to the tip are employed. In one system, the ink is stored in a narrow tubular reservoir that is connected to a tip. Ink flows from the reservoir through the tip by way of the capillary and gravitational forces.
Another system includes storing the ink in a fiber structure often referred to as a reservoir. The fiber reservoir is saturated with ink which flows from the fiber reservoir to the tip by way of both capillary and gravitational forces. The tip may be an extension of the fiber reservoir or may be a separate member with a collection tube or other structure that is embedded in the fiber reservoir.
Some instruments similar to writing instruments, require the application of pressure by way of the user's hand onto a flexible barrel containing the fluid to be dispensed in order to deliver the fluid through the tip. Specifically, instruments containing correction fluid are now offered in a “pen-shape” form which requires the user to apply pressure to the flexible barrel or reservoir in order to deliver correction fluid through the ball point tip. In contrast, fountain pens include a tip that is directly coupled to a liquid reservoir of ink and both capillary and gravitational forces deliver the ink to the fountain tip.
Further, more exotic writing instruments may include valve systems such as check valves or duckbill valves to help control the flow of ink or writing fluid to the tip. Such mechanical valve systems in writing instruments can be very costly due to the small size of such writing instruments. Further, mechanical valves can be unreliable due to the very nature of a writing instrument which is small, prone to be dropped or handled roughly and used in a wide range of ambient temperatures.
Thus, while writing instruments and correction fluid instruments may come in a variety of forms, none of the fluid delivery mechanisms are without their deficiencies. For example, while the capillary action of a ball point pen is dependable and long lasting, ball point pen apply a very thin coated of ink to the paper and are not preferred writing instruments by consumers for looking for bolder lines. On the other hand, felt tip pens provide a bolder, darker line but are prone to inconsistent ink delivery and premature drying out. Other roller-type pens that attempt to serve as a hybrid between a fountain pen and a ball point pen are prone to premature failure. Further, inexpensive pens that depend on gravity for ink flow will not work properly when the pen tip is disposed vertically above the ink reservoir.
Currently available correction fluid instruments that require the user to squeeze the barrel to apply the fluid operate inconsistently and are awkward to use due to the large amount of force required to be imposed upon the barrel in order to create the desired correction fluid flow. Any writing instrument with a mechanical valve disposed between the ink reservoir and the tip is expensive to manufacture and prone to failure for the reasons set forth above.
Therefore, there is a need for an improved fluid control system between an ink, paint, correction fluid or other liquid reservoir and a writing tip, brush or applicator tip.
Further, in the field of artist supplies, and more specifically, paint, an artist typically uses numerous brushes along with a pallet on which a variety of paint colors is disposed. While this system has been utilized for centuries, there is a demand for paint brushes that include their own reservoir of paint or ink which would eliminate the need for a separate pallet and, in the case of water colors, separate jars or bowls of water for the purpose of cleaning and wetting the brushes. Specifically, there is a demand for individual water color brushes which include a reservoir of water color connected to the brush. However, there currently is no satisfactory fluid control system for controlling the flow of water color from the reservoir to the brush tip. Thus, there is also a need for an improved control system for controlling fluid flow between a barrel reservoir and a brush tip of a water color paint brush applicator.